Afzal Ali, Mahreen Naima
Animal Sciences Division, Nuclear Institute for Agriculture and Biology College (NIAB-C), Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan.
School of Zoology, Minhaj University Lahore, Lahore, Pakistan.
Front Pharmacol. 2024 Mar 19;15:1375137. doi: 10.3389/fphar.2024.1375137. eCollection 2024.
Heavy metals, common environmental pollutants with widespread distribution hazards and several health problems linked to them are distinguished from other toxic compounds by their bioaccumulation in living organisms. They pollute the food chain and threaten the health of animals. Biologically, heavy metals exhibit both beneficial and harmful effects. Certain essential heavy metals such as Co, Mn, Se, Zn, and Mg play crucial roles in vital physiological processes in trace amounts, while others like As, Pb, Hg, Cd, and Cu are widely recognized for their toxic properties. Regardless of their physiological functions, an excess intake of all heavy metals beyond the tolerance limit can lead to toxicity. Animals face exposure to heavy metals through contaminated feed and water, primarily as a result of anthropogenic environmental pollution. After ingestion heavy metals persist in the body for an extended duration and the nature of exposure dictates whether they induce acute or chronic, clinical or subclinical, or subtle toxicities. The toxic effects of metals lead to disruption of cellular homeostasis through the generation of free radicals that develop oxidative stress. In cases of acute heavy metal poisoning, characteristic clinical symptoms may arise, potentially culminating in the death of animals with corresponding necropsy findings. Chronic toxicities manifest as a decline in overall body condition scoring and a decrease in the production potential of animals. Elevated heavy metal levels in consumable animal products raise public health concerns. Timely diagnosis, targeted antidotes, and management strategies can significantly mitigate heavy metal impact on livestock health, productivity, and reproductive performance.
重金属是常见的环境污染物,具有广泛的分布危害,与之相关的还有若干健康问题。重金属与其他有毒化合物的区别在于它们会在生物体中生物累积。它们污染食物链,威胁动物健康。从生物学角度来看,重金属既表现出有益影响,也表现出有害影响。某些必需的重金属,如钴、锰、硒、锌和镁,在微量时对重要的生理过程起着关键作用,而其他一些重金属,如砷、铅、汞、镉和铜,则因其毒性而广为人知。无论其生理功能如何,所有重金属摄入过量超过耐受限度都会导致毒性。动物主要通过受污染的饲料和水接触重金属,这主要是人为环境污染造成的。摄入后,重金属会在体内长期存留,接触的性质决定了它们会引发急性还是慢性、临床还是亚临床,或是轻微的毒性。金属的毒性作用会通过产生自由基导致氧化应激,从而破坏细胞内环境稳定。在急性重金属中毒的情况下,可能会出现特征性的临床症状,最终可能导致动物死亡,并伴有相应的尸检结果。慢性毒性表现为动物整体身体状况评分下降以及生产潜力降低。可食用动物产品中重金属含量升高引发了公众对健康的担忧。及时诊断、针对性解毒剂和管理策略可以显著减轻重金属对家畜健康、生产力和繁殖性能的影响。